The Mega Chaos Emerald
by Rosie the Echidna
Summary: Tails and Sonic find a strange new emerald in station square and it starts doing strange things to Sonic. Our favorite blue hedgehog has ungone a serious new situation! Read and find out what happens to our supersonic hero!
1. A New Emerald

**I just played the special demo for Pokemon Omega Ruby and Alpha Sapphire and it was awesome! Not only that, it gave me a great idea for a great Sonic the Hedgehog story by combing one of the concepts of the new Pokemon games with the Sonic fandom. I hope you like it! Enjoy!**

**I DO NOT OWN SONIC OR TAILS! THEY BELONG TO SEGA!**

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><p>It was another morning for Miles "Tails" Prowler as he was strolling Station Square, eating a chili dog that he just bought. He look around at the city scenery as he walked by. A few moments later, he walked by an ordinary trashcan, but there was something in it that caught the young fox's attention, a gleaming object that sparkled from the top of the pile of trash.<p>

"Huh? What was that?" Tails questioned.

He walked closer to the trash can and saw that the gleaming from a blue object, covered in trash, that appeared to be part of a gem.

"Hey, could that be a Chaos Emerald?!"

Curious, Tails reached in and grabbed the object from the trash can, revealing it to be a blue and red chaos emerald shaped gem. It definitely wasn't your everyday Chaos Emerald, having two colors at once. The gem shined in the kitsune's hand, radiating it's red and blue colors. When Tails got a closer look at it, he was one puzzled fox.

"Wait a minute... This isn't a Chaos Emerald." Tails concluded, "What is this?"

Just then, Sonic the Hedgehog sped up to the young fox from behind and greeted him.

"Hey Tails! How's it hanging?" Sonic greeted.

Tails turned around and saw his brotherly best friend standing in front him with a smile.

"Oh hey Sonic." Tails replied, "Hey look what I found in the trash." Tails showed Sonic the strange blue and red emerald he found earlier.

"Huh? It's that supposed to be a Chaos Emerald?" the confused hedgehog asked.

"I don't know. It doesn't look like usual chaos emerald. I think it could be something else."

"Let me see that."

Tails nodded and handed Sonic the blue and red emerald. He took a close look at it, seeing it radiate it's mysterious colors.

"Hmm... Let's see if works like a normal emerald." Sonic said as he brought it close to him and prepare to say those famous magic words.

"Chaos Control!"

As soon as Sonic said those words, the emerald began glowing brighter than before and shone its blue and red lights wildly. It gave off a bright blue and red flash making Sonic and Tails shield their eyes. As soon as the flash was over the emerald Sonic was holding suddenly disappeared into his body, Sonic didn't notice this. To his view, the emerald just plain disappeared.

"Whoa. What just happened?!" Tails asked, a little shooken up.

"I don't know. First it gives off a flash and then it vanishes just like that..." Sonic said.

After a few seconds, Sonic felt a sharp uneasiness inside his body, which made him lower his head and strain. His whole body was aching from the uncomfortable sensation inside him. Tails looked at him with high concern.

"Sonic! Are you okay?!" Tails exclaimed, worried.

"Argh... What's happening to me?!" Sonic exclaimed.

All of a sudden Sonic began to glow with bright blue light as a force field enveloped over him. It began to grow bigger and bigger until the force field burst open and reveiled Sonic with his entire body glowing light blue as it gave off a enlarged silhouette. Soon, the light faded and Sonic, who had his eyes closed, appearance drastically changed. His entire body was enlarged quite a bit and he grew more quills on his head and they were much larger, as well as the top two spines on his back. His arms were no longer peach, but light blue, with dark blue stripes, his shoes turned from red and white to navy blue and grey and the back of his legs had little blue spines, near the shoes. Sonic opened his eyes and felt all of the strain and pain he felt before leave his body. When he looked at himself and saw the drastic change, he was astonished. Tails was shocked too, for his best friend looked almost completely different. His eyes went wide.

"WHOA! WHAT THE HECK HAPPENED TO YOU?!" Tails yelled.

"I don't know, but I feel... stronger... Like some kind of new power just burst inside of me." Sonic described.

Tails then pulled out mech out of nowhere and used it scan Sonic's body. It was a scanner used to measure a person's power level, like a scouter. When Tails got the results from his scan read that Sonic power level increase exponentially.

"Wow! You weren't kidding!" Tails exclaimed, "You're power level just shot up at a high rate!"

"Did that emerald do this to me?" Sonic wondered.

"Maybe... but can't tell for sure right now. Let's get back to workshop and see if we can sort this out." Tails suggested.

"Good idea." Sonic agreed with a nod.

Sonic started sprinting back to Mystic Ruins, leaving behind a blue blur but also leaving behind a strong burst of wind that blasted Tails straight in the face and made him sheild his eyes. A big cloud of dust filled the area Sonic once was. Soon the cloud of dust disappeared and Tails stopped shielding his eyes to see that Sonic was long gone.

"Guess that power boost made him a lot faster too..." Tails sighed as he spun his two tails and started flying after the flying after the hedgehog.

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><p><strong>I guess you weren't expecting that! Well, what do you guys think? Was it creative or what?! I'm really proud of it! Oh and by the way, the cover picture you saw earlier? That's Mega Sonic! I plan on expanding the story later when I have some more time. Tell me what you think about it in the reviews until then. Sayonara for now!<strong>


	2. Digging into the Mystery

**Sorry I've been out for a while! I was helping a friend of mine write his first fanfiction story and afterwards I kind of dozed off. I'm back now and ready to continue this story! Here's the next chapter!**

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><p>As Tails closed in on Mystic Ruins and his workshop, he saw Sonic, still in his new transformation, waiting at the front door. He was tapping his foot impatiently, waiting for his twin-tailed friend to catch up. Soon, Tails made it to the workshop and landed in front of Sonic.<p>

"What took ya so long?" Sonic asked.

"Well excuse me! I didn't know that power boost enhanced your speed so much!" Tails said, a little annoyed.

"Yeah, I was a little surprised too." Sonic responded as he looked at his new appearance once more.

"Well lets head inside and see what happened to you."

Sonic nodded and followed his kitsune friend inside of his workshop. They walked past the living and headed downstairs to Tails' lab. The Laboratory was filled with robot parts, various types of high tech tools, scattered blueprints and a supercomputer at the back of the room. Even though Tails is usually hard at work, inventing and building, he always makes sure to keep everything clean and organized.

"All right. Let's get to the bottom if this," Tails declared.

"Heh. I'll leave it to you Tails!" Sonic smirked.

The brotherly duo proceeded to the back of the room and approached Tails' supercomputer. As Tails booted the machine up, he took another handheld mech, similar to his previous scanner mech, and scanned Sonic's body again. He then plugged it up to his supercomputer and transmitted the data. As he tinkered with the results, Sonic crossed his arms and tapped his foot again. He wasn't the one who likes to wait around, especially when Tails takes too long with his research.

"Is this gonna take any longer Tails?" Sonic groaned.

"Just a sec. I'm almost done." Tails reassured.

After a while longer of tinkering with the research findings, Tails was slightly surprised.

"Whoa... This is interesting!" Tails said.

"What did you find out?" Sonic questioned curiously.

"It seems that the emerald you absorbed gave off a special kind of energy that responded with your body and turned you into what you are now," Tails reported, "The intriguing thing is that the energy inside the emerald isn't exactly chaos energy, though it reacts when exert chaos control on it. It's more of a particular type of energy that I just can't put my finger on..."

Sonic took in everything his companion told him and thought about it a little.

"What do you think it could be?" Sonic asked.

"Hmm... I'm not sure. But I can say one thing. We discovered a new type of emerald. One that no one has ever seen before!"

Sonic nodded and smirked a little.

"Sounds pretty cool! It could be useful!" Sonic said.

Just then, Sonic's body gave off a light blue flash and Sonic's appearance returned to normal and the red and blue emerald was back in his hands.

"Hey! I'm back to normal!" Sonic announced.

Tails smiled and looked at the emerald in the hedgehog's hands.

"You think you could hold on to that a little longer?" Tails asked, "I think that emerald will be useful in the future. Plus, it seems the energy inside only responds to you."

"Sure! If this is a new kind of emerald, I'd love to see in action!" Sonic replied as he tossed the emerald in his hands a few times.

Sonic tucked the emerald into his hammerspace and started heading out of the lab.

"I'm heading out for a run. See ya Tails!" Sonic farewelled as he dashed out of the workshop.

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><p><strong>I'm currently working on Ch.3 now. It'll be coming soon and I'll try not to doze this time. Sayonara for now!<strong>


	3. Eggman Strikes Again

**Chapter 3 is ready to go! Now you'll see a little more of what Mega Sonic can do! Enjoy!**

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><p>After Sonic left Tails' Workshop, he went for a run around Mystic Ruins. He was taking his usual route, running through a wide, open, flowery plains, a lush green forest and around the hill which held Tails Workshop. Little did he know, a certain eggheaded villain was above him in his Egg Mobile, following his every move.<p>

"There's that troublesome hedgehog... And I seem to be picking up a certain energy source from him that looks like he's acquired a Chaos Emerald," the eggheaded human said to himself, "That Emerald will soon be mine!"

Eggman pulled ahead of Sonic and descended in front of him.

"Going somewhere hedgehog?" Eggman sneered.

"Eggman! What are doing here?" Sonic growled as he got battle ready.

"I detected that you have a Chaos Emerald! Now hand it over or I'll have to play dirty!" Eggman threatened.

"No way Egghead! You want it, you have to take it from me!" Sonic said, standing his ground.

"That can be arranged Hedgehog!" Eggman responded as he pressed a button on his Egg Mobile and summoned several of his Egg Pawns, little red robots with sometimes carry weapons, in front of the blue hedgehog. Some of the robots carried lances, guns and spiked shields. The all stood before Sonic in a menacing manner and were ready to fight but Sonic just scoffed.

"Yawn." Sonic mocked before using his signature homing attack to knock out all of the robots, making sure to not hit the spiked shields.

All of the robots on the field were now destroyed.

"Heh. Same as usual Egghead. All bark but no bite!" Sonic smirked.

"Then maybe these will show you not to mess with me!" Eggman barked as he pressed another button and summoned three heavy duty, large robots with giant hammers. They were a lot bigger than the other robots and posed more of a threat.

"Heh. This will be fun." Sonic smirked before reving up a spindash and charging at one of the robots. However, the attack merely bounced off the robot and no damage was dealt.

"Shoot! My Spin Attack isn't working!" Sonic exclaimed.

One of the robots tried swinging its huge hammer at Sonic but sped out of the way and tried using his homing attack. This time, he managed to knock the robot down as it fell with a loud thud. Sonic then noticed that a red metal cap fell off of the robot's head, revealing a small blinking bump on its grey head.

"That's got to be it's weak spot!" Sonic deducted.

He rev'd up his spin dash and and drove right into the robots head, cutting through its weak spot and bursting out the other side of it. The robot started glowing white then exploded.

"Ha! That's one dow- UGH!" Sonic got interrupted by a robot hammer swing which sent him flying a few feet. He landed, a little stunned, right next to another hammer wielding robot, who raised its hammer, ready to smash to cobalt hedgehog.

"OHHOHOHO! Your time is up Sonic! Say goodbye!" Eggman gloated.

The robot started swinging its hammer downwards at Sonic. The hedgehog closed his eyes and braced for impact but before the hammer made contact with him he heard a loud slice sound and then a loud thud. He opened his eyes to see the top of the robot's hammer was cut off and layed next to him. The robot looked at its broken hammer in confusion and Eggman was left shocked.

"What?! Who did that?!" Eggman exclaimed as he frantically looked around his surroundings.

"Over here Egghead!" a voice called out to him.

Everyone looked and saw a familiar pink echidna weilding a radiant pink Aura Sword in her right hand. It was Rosie. She looked at Eggman and his robots with a smug look on her face as her white headband flew in wind.

"I don't appreciate you treating my idol like that!" Rosie said at Eggman.

"You!" Eggman responded angrily.

Rosie walked over to Sonic and offered a hand up.

"Thought you could use a little backup," Rosie proposed.

"Thanks Rosie. You really came through there." Sonic replied as he accepted the hand up.

The two heroes stood before Eggman and the rest of his hammer weilding robots.

"So we meet again Egghead," Rosie smirked.

"I'd never thought I'd see you again you blasted echidna. What was your name again?" Eggman questioned.

"The name's Rosie. Rosie the Echidna! Ally of Sonic!" Rosie introduced.

"Well Rosie, prepare to meet your demise! I'll crush you and Sonic then I'll be rid of you both!" Eggman proclaimed.

"Don't count on it Ro-butt-nik! Ready to rumble Rosie?" Sonic called to his partner.

"Let's do it to it!" Rosie responded, assuming a battle stance with her sword.

One of the robots charged at the heroes again and swung his hammer at them. Rosie blocked it with her sword and attempted to slash at its body but the attack merely bounced off. She tried several more slashed at the robot but at no avail.

"Darn it! It's armor is too thick! I can't cut through it!" Rosie growled before jumping away from another hammer swing.

Sonic then eyed the robots' metal caps with suspicion.

"If we can just get those helmets off..." Sonic thought to himself.

Sonic proceeded to start running circles around the group of robots several times. He started picking up speed and formed a strong gust of wind that managed to blow the metal caps off of the hammer robots and expose their weak points. Sonic stopped next to Rosie.

"Aim for the blinking bump on their heads!" Sonic advised.

"Got it!" Rosie acknowledged as she ran toward the robot she was facing before.

She jumped up high to reach the robot's head and raised her sword.

"Hiiiyah!" Rosie slashed her way down from the robot's head, all the way to the ground and cut it completely in half. The two halves of the machine fell to the ground, along with the hammer and Rosie landed on her feet next to it.

"Well that one's done!" Rosie smirked.

Another robot swung its hammer down at Sonic but he sidestepped and dodged the attack. He jumped onto the hammer then up high, above the robot's head and came down with a spin dash, sawing through the it and coming through the other side. The robot exploded, marking the last one defeated.

"So much for your giant robots Egghead!" Sonic mocked.

"Is that so? Who said I didn't bring more?" Eggman said as he pressed another button on his mobile and summoned even more giant hammer robots. There was a whole army of them now and they all stood before Sonic and Rosie, ready to attack.

"OHHOHOHOHO! You don't stand a chance against my army of robots! You're done for!" Eggman bragged, thinking that he'd won already.

"Grr... What now?" Rosie growled.

It appeared to be a no win situation for the two but Sonic remembered the new emerald he found earlier. He pulled it out of his hammerspace and held it by his side. Rosie saw this and appeared surprised.

"No way! That couldn't be..." Rosie said in disbelief.

Sonic smirked and got ready for action.

"Heh. Time to kick this up a notch! Chaos Control!" Sonic said as the red and blue emerald activated.

The emerald gave off a blue and red flash before disappearing in Sonic's body. Sonic prepared himself for the strain as he started to transform. He started to glow blue and a force field enveloped him. Massive amounts of power was being realeased as the force field bursted open and revealed Sonic's new and enlarged form. Rosie and Eggman were shielding their faces as the shockwaves blew into their faces. When they saw Sonic's new look, Rosie was amazed and Eggman was shocked.

"What in the world?! What is this?!" Eggman panicked.

"Wow! Sonic underwent Mega Evolution!" Rosie pointed it out, smiling wide.

Sonic opened his eyes and gave Eggman a smug look.

"Wanna play hardball Eggman? I'll show ya some hardball!" Sonic taunted.

"Grr... I don't care what kind new transformation you went through! You're still no match for my army!" Eggman said.

Rosie stepped in, "Oh yeah? How about one more?" She pulled from her pocket, a strange pink and green Chaos Emerald shaped gem, very similar to Sonic's new emerald.

Sonic saw this and was a bit surprised.

"Huh? You have one too?" Sonic questioned.

"Yep! Okay Mega Emerald! Do you're thing!" Rosie said as she held her emerald up, "Chaos Control!"

Her emerald gave off a pink and green flash and disappeared into her body. She crossed her arms, closed her eyes and prepared for the strain as she started glowing bright pink. A pink force field covered her and got bigger and bigger until it burst to reveal Rosie's new form. Her fur turned dark pink, her hair grew a bit longer and her arms grew two white spikes on both sides. She uncrossed her arms and let out a huge battle cry, releasing a shockwave as her power was being released.

"HYAH!" She let loose her battle cry and huge amounts of energy was released, making Eggman shield his face again. Now he had two Mega Evolved opponents to deal with.

"Ready to give up Eggman?" Rosie smirked, floating in the air.

"Enough of this! I'll crush both of you right now!" Eggman snarled.

"Bring it Egghead!" Sonic taunted.

"Robots attack!" Eggman gave the order to the hammer weilding robots and they all started charging at the two.

Sonic rev'd up a spindash and suddenly darted forward in a flash of blue light. He crashed right into one of the heavy duty robots and pierced through its armor with ease. After the robot exploded, Sonic jumped into the air, spun into another spin dash and shot several blasts of wind at a group of robots, destroying them with one hit.

"Sweet! This power is pretty awesome!" Sonic admired before attacking more robots.

Rosie summoned her Aura Sword again, a lot bigger this time, and began hacking and slashing at several robots in front of her. One robot tried swinging its hammer at her but Rosie countered with her sword and sliced it into pieces. She then dashed straight through the robot with her sword and did a spin dash through several more. When another robot got close, she grabbed it by the foot and spun it around a bunch of times, hitting other nearby robots in her path. Then she slammed into the ground.

Sonic destroyed many more robots with his upgraded spindash attacks. and another robot came at him with its hammer. Sonic jumped up high to evade and when he was high in the air, the top two spines on his back extended like a pair of wings. He came falling straight down headfirst, glowing in a bright blue light. Right before he hit the ground, he swooped up and flew straight at the robot, glowing a harsh white light now. He pierced through the robot he was facing.

"WOOHOO!" Sonic continued darting forward to crash through a huge amount of robots, soaring like hypersonic jet plane. He soon shifted his body up and landed on his feet as the robots behind him, with giant holes in their chests, all fell and exploded. A trail of windy turbulence could be seen in the path he flew through a second ago and it died out slowly.

"That was awesome!" Sonic cheered as his top two back spines shrunk back to normal.

Rosie slashed a whole group of robots to pieces with her sword and one more robot came at her but she saw it coming and charged her sword with aura energy and swung it upwards, hitting the robot and knocking it upwards. She quickly flew up after it and readied her sword.

"Aura Ninja Pummel!" Rosie started dashing at it from the air, nimbly striking the robot from many different directions like a ninja. After several more strikes, she appeared above it and slammed it back down to the ground. It landed on top of the remaining robots and caused a big explosion, destroying the last of the hammer robots. Rosie landed back to the ground and put away her Aura Sword.

"Aww yeah! That's the last of them!" Rosie cheered.

Sonic and Rosie looked toward Eggman, who had his face covered in smoke from the last explosion.

"This looks like checkmate doctor!" The two said in unison.

"Grr... This isn't over!" Eggman growled at the two.

And with that, Eggman flew away and left the two alone. Sonic and Rosie smiled at each other and did a high five.

"Nice going Rosie! I appreciated your help out there!" Sonic praised.

"You were awesome too Sonic! I never thought you had a mega evolution!" Rosie replied.

Sonic cocked a brow in confusion. "Mega evolution?"

"You don't know what a Mega Evolution is? It's when you use a special Mega Emerald to transform into stronger version of yourself, called a Mega form." Rosie explained.

"Mega evolution... So that's what this is..." Sonic said to himself.

"Hmm. Maybe I should explain more about but first lets get to a discrete location." Rosie suggested.

Sonic nodded and the two set off for Tails' Workshop.

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><p><strong>After a harsh battle against Eggman, Sonic's going to learn a little more about his new emerald and his transformation. What will he find out? The final chapter is coming next so stay tuned!<strong>


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